Hammer mill



May 14, 1929 Gpw. BoR'roN 1,713,327

' HAMMERMILL Filed Feb. 14, 1928 Patented May 14, y1929.

UNITED STATES 1,113,321 f/PATENT. OFFICE.

GEORGE BORTON, OF' NEW LISBON,` NEW JERSEY, ASSIGNOR TOgPENNSYLVANIA CRUSHER COMPANY, OF NEW YORK, N. Y., A CORPORATION 0F NEW YORK.

HAMMER MILL.

yApplication led February 14, 1928. Serial No. 254,235.

This invention relates to hammer mills, .and relates more particularly to a novel and highly advantageous construction inl those parts providing the breaking surface.

The principal object of the invention is to provide a breaking surface V'which is selfcleaning and which prevents the accumulation of dust and other materials on the breaking surfaces, or pluggin up, with the consequent material loss in e cien'cy.

. Another object of the invention is to provide a breaking surface structure having selfcleaning vcharacteristics actuated by the impact of the materials impelled against the breaking surface by the hammers'.

In the attached drawings, in which I have illustrated a hammer mill of the bottom running type:

Figure 1 is a more or less diagrammatic sectional View showing sutlicientof the de* tails of a hammer mill to afford an understanding of the invention, and

Fig. 2 is a section on the line 2-2, Fig. 1.

With reference to thedrawings, 1 represents the casing or housing of the mill and 2 the rotary shaft which carries a rotor 3 having the pivoted hammers 4. As previously stated, the hammer Crusher is of the type known as bottom running, and the rotor 3 with the hammers isI accordingly rotated in the direction of the arrow, see Fig. 1. The material is fed into the casing at the top and is impelled by the rotating hammers against the upper breaking plate or surface 5, and thereafter against and over the surface of the cage 6,\which in the present instance is piv-kr otally mounted at one end on a transverseshaft 7 The upper or advance end of the cage 6, as clearly illustrated in Fig. 1, comprisesa plurality of independent bars 8 pivotally mounted upon a transverse shaft 9 in the cage structure, and the bars 8 form a breaking and crushing surface against which the material is impelled by the hammers in well known manner. In back of or underneath the upper y'and lower ends of the series of bars 8 are stop shafts or transverse rods 10, 10, which limit the oscillatory movement of the bars 8 around the shaft 9 upon which theyv are ,journaled lPreferably the shaft 9 is nor rmal tothe general' direction in which material entering the crusher is impelled by the hammers, and the rods 10, 10, prevent a material departure of the bars 8 froml a plane normal to the direction of movement of the said material.A

Although not essential to the invention, I prefer to provide at the back of each of the bars 8, secured thereto respectively on each side of the shaft 9, a pair of springs 11 and 12 which also are adjustably secured to the housing 1 by means of the threaded eye boltsY 11 may be adjusted through the studs 13 andadjusting nuts 15 to provide a proper flexible balance in the bars 8.

When material is fed into the housing 1 and is impelled by the hammers 4 a ainst the surface formed by the bars 8, a vi ratory or oscillatory movement will` be set up therein around the pivot bar 9, this movement being controlled by the springs 11 and 12, the bars being returned after each successive shock to a normal position by the springs. By reason of the vibrator-y or oscillatory movement set up in the bars, and the shock due to impact ofl the bars against the stop bars 10, material such as wet dust or other adherent substances,

having a tendency to fill the spaces between the bars and `eventually to cover the bars'in auchv manner as toreduce their operating eflficiency, will be ,shaken or jolted from the ars.

It will be noted that the vibratory or oscillatory movement of the bars is set up by the material impelled against them in normally passing through the mill. Attention is 4also directed to the extremely desirable action obtained by the described arrangement of parts, combining a vibratory movement of the bars around the shaft 9 with a severe shock due to the impact of the ends of the bars against the respective stop bars 10, 10 tendin tojdisodge any substances adhering to the bars, and thereby keeping them clean.

Although I have illustrated and described the bars as having associated springs 11 and les 12, it will be apparent that these springs may under some circumstances be entire y eliminated Without departure from Vthe es .sential features of the invention, the irregular impact of the material on opposite sides of the transverse journal bar 9 being suflicient to set up the desired vibration or oscillation of the bars, with consequent shock arising from impact against the stop bars.

The type of material passing through `the mill and the particular conditions of operation-Will determine Whether or not to disi pense With the springs and to otherwise 'modify the structure. It may for example be desirable to place the transverse bar 9 toone side ofthe middle of the bars 8, and

the center ofoscillation maybe thus so lono sense limited to the particular applicationl herein illustrated'and described., i

I claim: Y

1. A hammer mill comprising a housing, a rotor'in saidhousing including a plurality of hammers, means for feeding material into the housing so as to be brought into engagementwvith the hammers, and a structure providing a crushing surface against Which the said material is impelled by the hammers,

said structure including a transverse shaft and a plurality oflbars pivotally mounted on said shaft intermediate their ends and oscillatable under impact of said material, and means for limiting the oscillatory movement of the bars in both directions.

2.,'A hammer mill comprising a housing,

a plurality of rotary hammers mounted for notation in the housing, and a self-cleaning crushing surface against which the hammers 'are' adapted to impel a material introduced into the mill, said crushing surface structure including a plurality of surface forming bars lpivotally mounted in spaced and substanlcrushing surface against which the hammers are adapted to impel a material introduced into the mill, said crushing surface structure including a plurality of surface forming bars mounted for oscillation in spaced and substantially parallel relation adjacent the rotor,

'and resilient means controlling the oscilla tion of said bars.

4. A hammer mill comprising a housing, a plurality of rotary hammers mounted for rotation inthe housing, and a self-cleaning crushing surface against which the hammers are adapted to impela material introduced into the mill, said crushing surface structure including a plurality of'surface .forming bars mounted for oscillation in spaced and substantially parallel relation adj acnt the rotor, and resilient means controlling the oscillation of said bars, with positive stops limiting the oscillation of said bars.

5. A hammer mill comprising a housing, a rotor in said housing including a plurality of hammers, means for feeding material into the housing so as to he brought into engagement with the hammers, and a structure providing a crushing surface against which the said material is impelled by the hammers,

said structure including a transverse shaft and a plurality of surface-forming bars mounted for oscillation under impact of said material about-an axis intermediate the ends thereof, and stops limiting oscillation in both impacting material and oscillatable underl said impact, and means for limiting t-he oscillation of the bars in both directions so that the bars cannot materially depart from .a plane normal'to the movement of said impactmg material.

` GEORGE W. BORTON. 

